What is the appropriate treatment for a urinary tract infection caused by Enterococcus faecalis?

Treatment of Urinary Tract Infection Caused by Enterococcus faecalis

Ampicillin or amoxicillin is the first-line treatment for urinary tract infections caused by Enterococcus faecalis, as these organisms are typically susceptible to penicillins. 1

First-Line Treatment Options

For uncomplicated UTI caused by E. faecalis:

• Oral options:

  • Amoxicillin 500 mg every 8 hours or 875 mg every 12 hours for 7-10 days 1
  • Nitrofurantoin 100 mg PO every 6 hours 2, 3
  • Single dose of fosfomycin 3 g PO 2

• Parenteral options (for complicated infections):

  • Ampicillin 2 g IV every 4-6 hours 2
  • Piperacillin-tazobactam (for more severe infections) 2

Treatment Algorithm

1. Assess infection severity:

   • Uncomplicated UTI (cystitis): Oral therapy
   • Complicated UTI or pyelonephritis: Consider parenteral therapy initially

2. Check susceptibility results:

   • E. faecalis is typically susceptible to penicillins 1, 4
   • Note that the lab report mentions "Enterococci susceptible to penicillin are predictably susceptible to ampicillin, amoxicillin, ampicillin-sulbactam, amoxicillin-clavulanate, and piperacillin-tazobactam"

3. Select appropriate antibiotic:

   • For uncomplicated UTI: Amoxicillin (first choice), nitrofurantoin, or fosfomycin
   • For complicated UTI: Ampicillin IV or piperacillin-tazobactam

Special Considerations

• Catheterized patients: Consider catheter removal if possible, as enterococcal UTIs are common in catheterized patients 5

• Underlying urologic abnormalities: Patients with E. faecalis UTIs have higher rates of underlying urinary tract abnormalities that may require further evaluation 6

• Immunocompromised patients: May require longer treatment duration or combination therapy 2

• Vancomycin-resistant strains: If suspected, consult infectious disease specialist. Options include linezolid or daptomycin 2

Important Caveats

• Cephalosporins are NOT effective against enterococci despite in vitro susceptibility
• Trimethoprim-sulfamethoxazole is generally not effective against enterococci 2
• Aminoglycosides alone have poor activity against enterococci and should only be used in combination therapy for severe infections 5
• Asymptomatic bacteriuria with enterococci generally does not require treatment unless the patient is pregnant or undergoing urologic procedures 5

Duration of Therapy

• Uncomplicated UTI: 7-10 days
• Complicated UTI or pyelonephritis: 10-14 days
• Treatment should be continued for at least 48-72 hours after the patient becomes asymptomatic 1